Tunable large Berry dipole in strained twisted bilayer graphene

Pantaleón, Pierre A.; Low, Tony; Guinea, F.

doi:10.1103/physrevb.103.205403

Cited by 54 publications

(43 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Beyond the redesign of energy dispersion, however, is the ability of moiré materials to alter the texture of Bloch wavefunctions. For instance, twisting atomic layers allows the design of topological Bloch bands formed out of topologically trivial constituent layers [9][10][11][12][13][14], as well as the control of strong concentrations of Bloch band quantum geometric quantities such as Berry curvature density [15,16]. Given the intimate relationship between band geometry and optical nonlinearities [17], moiré materials are expected to host pronounced nonlinear photocurrent responses [18,19].…”

mentioning

confidence: 99%

Strain-induced large injection current in twisted bilayer graphene

Arora,

Kong,

Song

2021

Preprint

View full text Add to dashboard Cite

mentioning

confidence: 99%

Strain-induced large injection current in twisted bilayer graphene

Arora,

Kong,

Song

2021

Preprint

View full text Add to dashboard Cite

“…In comparison, twisted bilayer graphene displays a BCD two orders of magnitude higher than TMDCs. This higher value, when compared to TMDCs, has also been attributed to narrower bands and concentration of Berry curvature around the gapped Dirac cone in this system [73]. It would further be interesting to explore the strain-tuning of BCD in our Janus structures, since it has been shown that Berry curvature in TMDCs can be efficiently controlled using strain [74,75].…”

Section: Berry Curvature Dipolementioning

confidence: 78%

Tunable topology and berry curvature dipole in transition metal dichalcogenide Janus monolayers

Joseph

Roy

Narayan

2021

Mater. Res. Express

View full text Add to dashboard Cite

Janus transition metal dichalcogenides, with intrinsic mirror asymmetry, exhibit a wide array of interesting properties. In this work, we study Janus monolayers derived from WTe2 using first-principles and tight-binding calculations. We discover that WSeTe and WSTe are topologically trivial, in contrast to the parent quantum spin Hall insulator WTe2. Motivated by the growing interest in non-linear Hall effect, which also requires asymmetric structures, we investigate the Berry curvature and its dipole in these Janus systems and find that they exhibit strikingly large values of Berry curvature dipole, despite being in the topologically trivial phase. We track down the origin of this behaviour and put forth a low-energy massive Dirac model to understand the central features of our ab inito computations. Our predictions introduce Janus monolayers as promising new platforms for exploring as well as engineering non-linear Hall effect.

show abstract

“…Such processes can be made to contribute to the nonlinear optical response by applying a strain as discussed in Ref. [38,89]. In TBG, we expect the strain-induced contribution to be of the same order of magnitude [55] and therefore should not alter our results drastically.…”

Section: Discussionmentioning

confidence: 91%

“…Many interesting signatures of QG are revealed in transport properties and optical responses of these systems [12][13][14][15][16][17][18][19][20][21][22], and especially in the zero-magnetic field quantized anomalous linear hall effect in setups with time-reversal symmetry (TRS) [5,11,23]. The effects of QG go well beyond linear response, and can manifest themselves in nonlinear optical responses (NLOR) as shown recently [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Furthermore, the NLOR does not require broken TRS, but rather a non-zero Berry curvature profile.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the NLOR does not require broken TRS, but rather a non-zero Berry curvature profile. These nonlinear effects can manifest in various ways, such as nonlinear response to DC fields (induced by Berry curvature dipole [24,28,29,[35][36][37][38][39]), second-harmonic generation (SHG), and bulk-photovoltaic effects like shift-current (SC) [30,31,33,40], and circular photogalvanic effects (CPGE) [26,41,42]. Recently, there has been a lot of emphasis on the non-linear response to AC fields [25,42,43] which not only serve as a probe of non-trivial topology but also heralds promises of more efficient and robust photovoltaic devices [34].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Shift-current response as a probe of quantum geometry and electron-electron interactions in twisted bilayer graphene

Chaudhary,

Lewandowski,

Refael

2021

Preprint

View full text Add to dashboard Cite

Moiré materials, and in particular twisted bilayer graphene (TBG), exhibit a range of fascinating phenomena, that emerge from the interplay of band topology and interactions. We show that the non-linear second-order photoresponse is an appealing probe of this rich interplay. A dominant part of the photoresponse is the shift-current, which is determined by the geometry of the electronic wave-functions and carrier properties, and thus becomes strongly modified by electron-electron interactions. We analyze its dependence on the twist angle and doping, and investigate the role of interactions. In the absence of interactions, the response of the system is dictated by two energy scales: the mean energy of direct transitions between the hole and electron flat bands, and the gap between flat and dispersive bands. Including electron-electron interactions, both enhance the response at the non-interacting characteristic frequencies as well as produce new resonances. We attribute these changes to the filling-dependent band renormalization in TBG. Our results highlight the connection between non-trivial geometric properties of TBG and its optical response, as well as demonstrate how optical probes can access the role of interactions in moiŕe materials.

show abstract

Tunable large Berry dipole in strained twisted bilayer graphene

Cited by 54 publications

References 54 publications

Strain-induced large injection current in twisted bilayer graphene

Strain-induced large injection current in twisted bilayer graphene

Tunable topology and berry curvature dipole in transition metal dichalcogenide Janus monolayers

Shift-current response as a probe of quantum geometry and electron-electron interactions in twisted bilayer graphene

Contact Info

Product

Resources

About